The study, published in Frontiers in Animal Science, was led by Andrew Knight of Murdoch University, together with Alexander Bauer and Jenny L. Mace. The team conducted a cross-sectional online survey of companion animal carers, open from May to December 2020, which gathered information on the health of one resident cat per household that had lived there for at least a year. From a larger pool of 4,057 dog and cat carers, 1,397 cat carers met the inclusion criteria, and 1,305 cats were ultimately analysed across the two diet groups of interest: 1,178 cats, or 90.3 percent, fed conventional meat-based diets, and 127 cats, or 9.7 percent, fed vegan diets for at least one year. Carers reported the assessments of their primary veterinarians concerning the cats’ health over the previous twelve months.

The researchers focused on six body weight-related disorders: overweight, underweight, osteoarthritis or arthritis, intervertebral disc disease, other mobility disorders, and other musculoskeletal problems. According to the carer-reported veterinary assessments, only 3.1 percent of vegan-fed cats were classified as overweight, compared with 4.1 percent of meat-fed cats. In unadjusted statistical analyses, cats fed vegan diets had odds of being overweight that were 24 percent lower than their meat-fed counterparts. When the researchers adjusted for ten potential confounding variables, including age, sex, neuter status, activity level and a range of feeding practices, the difference widened to 34 percent lower odds of overweight in the vegan group.

Here is the crucial caveat: neither figure reached statistical significance. The confidence intervals were wide, spanning from a 73 percent reduction to a 116 percent increase in the unadjusted overweight analysis, reflecting the relatively small number of observed cases. Only four vegan-fed cats were classified as overweight at all. The authors interpreted the raw 24 percent effect as a “tendency” and the adjusted 34 percent effect as a “strong tendency,” using heuristic categories they established in earlier work on general health outcomes from the same survey. Following the American Statistical Association’s guidance on p-values, they emphasised effect strength over binary significance thresholds, but they are explicit that the findings should be treated as hypothesis-generating rather than confirmatory.

The pattern extended to underweight as well. Cats fed vegan diets showed 66 percent lower odds of being underweight in the unadjusted models, a difference the authors labelled a strong tendency, though again it was not statistically significant. More striking still were the secondary outcomes: not a single vegan-fed cat in the sample was reported to suffer from osteoarthritis or arthritis, intervertebral disc disease, other mobility disorders, or other musculoskeletal problems. Among the meat-fed group, 15 cats had arthritis impairing mobility, one had intervertebral disc disease, eight had other mobility problems and 14 had other musculoskeletal problems. Because zero cases occurred in the vegan group, the researchers could not run regression models for these outcomes at all, and the low prevalence likely reflects the small size of the vegan subgroup rather than any proven protective effect.

The statistical machinery behind the study was deliberately cautious. The analysis proceeded in three steps: a descriptive stage, an exploratory stage estimating the diet effect with ten separate one-variable regression models, and a final fully adjusted model restricted to outcomes with at least 50 cases across both diet groups, a criterion met only by overweight. That final model produced an area under the curve of 0.78 on a held-out test set, indicating acceptable fit. Two sensitivity analyses bolstered the findings: propensity score matching on age, which matters because vegan-fed cats averaged 6.2 years old versus 8.2 years for meat-fed cats, yielded broadly similar reductions of 21 percent in overweight and 50 percent in underweight odds. And when 64 raw-meat-fed cats were folded into the meat-based comparison group, the results barely moved, with the adjusted overweight effect shifting by just one percentage point.

Why might plant-based diets be associated with leaner cats? The authors cannot answer definitively, since they collected no compositional data, but they outline plausible mechanisms. Nutritional guidelines for weight management in cats favour lower calories, lower fat, higher fibre and higher L-carnitine content. Plant-derived ingredients often contain more fibre and potentially fewer calories or less fat than animal sources. More intriguingly, conventional cat foods are not required to guarantee L-carnitine, a vitamin-like amino acid derivative critical for energy metabolism and the retention of lean body tissue, because manufacturers assume meat supplies adequate quantities. Some nutritionally sound vegan cat foods, by contrast, are explicitly supplemented with L-carnitine, potentially offering cats greater protection against weight gain. There is also a paradox worth noting: vegan-fed cats in this sample were actually more often fed dry food and fed ad libitum, both factors previously associated with increased overweight risk, yet they still showed lower odds of excess weight.

The study also surfaced a striking discrepancy in how weight was judged. Veterinarians reportedly considered 94 percent of meat-fed cats and 96 percent of vegan-fed cats to be at ideal weight, while carers’ own opinions put those figures at 70 percent and 76 percent respectively. Usually the reverse is true, with owners less likely than vets to recognise overweight. The authors suggest several explanations: carer concern may capture perceived adiposity rather than clinically communicated problems; body condition scoring is under-recorded in practice, with a UK study of 129,076 cat visits finding weight recorded in only 10 percent of visits; and surveys may attract more health-conscious carers. The very low 4 percent veterinary-reported overweight prevalence in this sample contrasts sharply with estimates of 30 to 60 percent from veterinary-assessed studies, which may mean the study underestimated overweight overall, a limitation the authors acknowledge candidly.

That said, the limitations extend further. All outcomes relied on carer reports, introducing potential recall and reporting bias, and carer-reported assessments are not equivalent to standardised veterinary body condition scoring. Social desirability bias among vegan-feeding carers, possible confounding by unmeasured health-protective behaviours, and survivorship bias, in which cats harmed by vegan diets are switched back to meat and vanish from the vegan group, cannot be excluded. The analysis also excluded endocrine, urinary, cardiac and dermatological comorbidities of obesity. The fully adjusted model, with only four overweight events in the vegan group, fell short of the traditional ten-events-per-parameter rule of thumb for logistic regression.

What the study does deliver is a consistent direction of effect across every model the authors ran, a robustness to alternative analytical choices, and a clear roadmap for future work. Larger samples, prospective designs, direct extraction of veterinary-recorded body weights and standardised body condition scores, and measurement of actual diet composition and energy intake would all help resolve whether the leaner-cats pattern is real. For now, the message is nuanced: among these 1,305 cats, vegan-fed animals fared no worse on body weight and related disorders than meat-fed ones, and descriptively better, but nobody should yet conclude that vegan diets slim down cats. This is exploratory science, published transparently with its uncertainty on display, precisely so that the next generation of studies can test the hypothesis properly.

Subject of Research: The association between vegan versus meat-based diets and body weight-related disorders in domestic cats

Article Title: Impacts of a vegan diet on body weight and related health disorders in 1,305 cats: an exploratory cross-sectional survey

Article References: Knight, A., Bauer, A., & Mace, J. L. (2026). Impacts of a vegan diet on body weight and related health disorders in 1,305 cats: an exploratory cross-sectional survey. Frontiers in Animal Science, 7, Article 1939965. https://doi.org/10.3389/fanim.2026.1939965

Image Credits: AI Generated

DOI: 10.3389/fanim.2026.1939965

Keywords: cats, vegan cat food, feline obesity, overweight, body condition score, pet nutrition, veterinary epidemiology, cross-sectional survey, logistic regression, obligate carnivores, L-carnitine, pet health

The research team, led by Gökşad Cemil Kotan, Şeyma Aydemir, and Bülent Bayraktar of Hitit University and Bayburt University, set out to answer a deceptively simple question: how does a dairy cow’s body chemistry change as she moves through the six major stages of her production cycle? To do this, they enrolled multiparous Brown Swiss cows at a large commercial dairy operation in Çorum, Türkiye, and divided them into eighteen subgroups of twenty animals each. The groups crossed three pregnancy stages, early, mid, and the dry period in the final sixty days before calving, with three lactation stages, early, mid, and late, and then crossed each of those with three body condition score categories. Blood was drawn from the jugular vein, serum was separated and frozen at minus eighty degrees Celsius, and a battery of biochemical assays followed.

The analytical toolkit combined old and new. Traditional metabolic markers, non-esterified fatty acids (NEFAs), beta-hydroxybutyrate (BHBA), urea, albumin, globulin, and total cholesterol, were measured on a Roche Cobas 8000 analyzer using spectrophotometric methods. But the real novelty lay in the four molecules measured with bovine-specific enzyme-linked immunosorbent assays: the adipokines spexin, irisin, and visfatin, and the endoplasmic reticulum stress marker GRP78. These are molecules that have attracted intense interest in human metabolic research but remain poorly charted in cattle, particularly across the full arc of pregnancy and lactation in a single breed.

Why do these particular molecules matter? Adipose tissue is not merely a passive fat warehouse; it is an endocrine organ that secretes hormones regulating appetite, insulin sensitivity, and energy expenditure. Spexin, a small neuropeptide, has pleiotropic effects including the regulation of insulin resistance, glucose levels, and lipid metabolism, and it appears to suppress fat accumulation in the liver by stimulating lipolysis while inhibiting lipogenesis. Irisin, a proteolytic fragment of the membrane protein FNDC5, is released largely by skeletal muscle and drives the browning of white adipose tissue, raising energy expenditure and thermogenesis. Visfatin, also known as nicotinamide phosphoribosyltransferase or NAMPT, mimics insulin’s effects on glucose utilization and participates in NAD biosynthesis, linking cellular energy state to whole-body metabolism. GRP78, meanwhile, is a seventy-eight kilodalton chaperone protein of the HSP70 family that resides in the endoplasmic reticulum, where it orchestrates protein folding and triggers the unfolded protein response when folding capacity is overwhelmed, a condition known as ER stress.

The statistical design was rigorous. A two-way factorial analysis of variance tested the effects of physiological stage, body condition score, and their interaction on every measured parameter, with Duncan’s multiple range test used for post hoc comparisons. The interactions between physiological stage and body condition were highly significant for all measured parameters, at p less than 0.001, meaning that a cow’s fatness and her reproductive-lactational state do not act independently on her metabolism but rather in concert. That finding alone carries practical weight, because it suggests that feeding and monitoring strategies cannot be one-size-fits-all across a herd.

The headline results concern the timing of stress. Serum GRP78 peaked during the dry period, reaching a maximum of 0.46 nanograms per milliliter, and remained elevated in early lactation before declining as metabolic stability returned. NEFA, the classic blood signature of fat mobilization, followed the same pattern, peaking at 0.52 millimoles per liter during the dry period, well above the 0.40 millimoles per liter threshold generally used to flag excessive lipolysis. Urea levels also peaked in the dry period and early lactation. Strikingly, during the dry period these stress markers rose even as albumin and globulin, markers of hepatic synthetic capacity and immune status, declined significantly. In other words, the weeks before calving, long before a drop of milk is produced, appear to be the moment when the cow’s cellular machinery is under the greatest strain.

The adipokine story provides the counterpoint. Spexin ranged from a low of 14.02 picograms per milliliter in early pregnancy to a high of 36.04 picograms per milliliter, with levels rising as pregnancy and lactation progressed and showing an inverse relationship with body condition. Irisin climbed steadily from the onset of lactation, from a low of 0.95 nanograms per milliliter in early-lactation thin cows to 2.07 nanograms per milliliter in late-lactation cows with high condition scores, and peaked at 2.66 nanograms per milliliter during the dry period. Visfatin rose specifically during gestation, peaked at 24.09 nanograms per milliliter during the dry period, and continued climbing as lactation advanced toward the late stage. The authors interpret this coordinated rise as evidence of successful metabolic adaptation: as negative energy balance eased, these hormones helped restore insulin sensitivity and energy homeostasis.

Notably, the cows in this study managed the transition remarkably well. Early-lactation NEFA values of 0.34 to 0.41 millimoles per liter and BHBA values of 0.38 to 0.48 millimoles per liter stayed below or near the physiological thresholds for ketosis, and BHBA remained within normal limits throughout. Total cholesterol rose by roughly twenty-two percent across gestation and thirty-four percent across lactation, mirroring the recovery of feed intake and hepatic lipoprotein synthesis as energy balance improved. The researchers attribute this resilience partly to the Brown Swiss breed, which tends to mobilize body reserves more conservatively than high-yielding Holsteins and possesses a robust muscular conformation that may boost irisin secretion. In healthy animals, the GRP78 surge appears to be a protective physiological adaptation rather than pathological ER stress, a sign that the unfolded protein response is keeping pace with the enormous metabolic workload of late pregnancy and milk synthesis.

The authors are candid about limitations. Commercial ELISA kits for bovine matrices, especially for cleaved peptides like irisin, remain a subject of analytical debate, and the team recommends future validation by mass spectrometry or western blotting. No tissue biopsies were taken, so circulating biomarkers could not be linked directly to gene expression in adipose or hepatic tissue. Still, the practical implications are clear. Because spexin and GRP78 track lipolysis intensity and cellular stress so closely, they could serve as prognostic biomarkers for the early detection of metabolic stress and ketosis risk, allowing targeted nutritional interventions and antioxidant strategies during the dry period rather than generic herd-level management. For an industry where subclinical metabolic disease quietly erodes fertility, milk yield, and profitability, a blood test that flags trouble weeks before clinical signs appear could change how transition-period cows are fed, monitored, and protected, turning one of dairying’s most dangerous windows into a manageable, measurable event.

Subject of Research: Metabolic adaptation and adipokine and ER stress biomarker dynamics across pregnancy and lactation in Brown Swiss dairy cows

Article Title: Metabolic, adipokine (irisin, spexin, visfatin), and ER stress (GRP78) responses in multiparous Brown Swiss cows: a multivariate approach across physiological stages and body condition scores

Article References: Kotan, G. C., Aydemir, Ş., & Bayraktar, B. (2026). Metabolic, adipokine (irisin, spexin, visfatin), and ER stress (GRP78) responses in multiparous Brown Swiss cows: a multivariate approach across physiological stages and body condition scores. Archives Animal Breeding, 69(3), 517-528. https://doi.org/10.5194/aab-69-517-2026

Image Credits: AI Generated

DOI: 10.5194/aab-69-517-2026

Keywords: dairy cattle, Brown Swiss, adipokines, spexin, irisin, visfatin, GRP78, endoplasmic reticulum stress, negative energy balance, NEFA, body condition score, transition period

The study, led by Rogers Kigoonya of the Namayingo District Local Government together with colleagues at Makerere University, was conducted between July and October 2024. Namayingo is an unusual place for cattle research. The district, which covers 532.9 square kilometers of Lake Victoria territory near the Kenyan border, historically depended on fishing. As fish stocks dwindled, communities transitioned into subsistence farming that integrates small-scale cattle and crop production. Today, of the 11,384 cattle-keeping households in the district, more than half own only one or two animals, and 98.6 percent of the district herd consists of indigenous breeds. Despite the economic importance of these animals, scientific data on their reproductive performance in the district had been almost entirely absent.

To fill this gap, the team used a multi-stage sampling design targeting smallholder farmers in the sub-counties of Buyinja, Buhemba, Banda, and Mutumba. Data came from three sources: physical examination of the cattle, direct observation of farm management practices, and a pre-tested structured questionnaire administered to 90 farmers. Pregnancy status was determined through a combination of farmers’ reports of non-return to heat, visual observation, and rectal palpation performed by a veterinarian using a standardized protocol. Body condition scores were recorded on a five-point scale, and calving intervals were calculated from the two most recent consecutive calvings to minimize recall bias. Farmers with more than six cattle were excluded, keeping the study firmly focused on the smallest production units.

The headline numbers reveal a system operating below its potential. The average calving interval was 13.8 months, exceeding the 12-to-13-month benchmark recommended for achieving one calf per cow per year, the standard reproduction index for profitable cattle keeping. Services per conception averaged 1.48, meaning cows typically required roughly one and a half matings or inseminations before conceiving. Repeat breeding, defined as failure to conceive after three or more services, affected only 2.1 percent of cows, a remarkably low figure that the researchers attribute to the resilience of indigenous breeds. Dystocia, or difficult calving requiring assistance, told a far grimmer story: at 15.2 percent, it was roughly three times the internationally reported rate of less than 5 percent and well above figures documented elsewhere in East Africa.

The dystocia finding is particularly consequential for calf and cow survival. The researchers suggest the high prevalence may stem from the composition of the study herd, since 40.2 percent of cows were primiparous, meaning they were calving for the first time with pelvic structures that are not yet fully developed. In addition, the dominance of indigenous cattle raises the likelihood of mismatches between sire and dam sizes, both through artificial insemination with inappropriate semen and through uncontrolled natural mating with bulls of unknown conformation. Difficult calvings delay the return of ovarian activity, lengthen the time to the next conception, and can permanently damage fertility, making this single statistic a plausible driver of the extended calving intervals observed across the district.

When the team ran multivariable binary logistic regression on pregnancy status, three factors emerged as decisive. Body condition score, a direct proxy for nutritional status, was highly significant, echoing decades of evidence that thin cows suffer from anestrus, delayed conception, and reduced fertility. Housing mattered as well: cows kept in shelters had more than four times the odds of being pregnant compared with cows without any housing (odds ratio 4.24, 95 percent confidence interval 1.34 to 13.45). Shelter reduces environmental stress and protects animals from injuries that compromise fertility. Management system also exerted a strong effect, with tethered cattle showing drastically reduced odds of pregnancy compared with zero-grazed animals, an odds ratio of just 0.033. Alarmingly, 83.3 percent of farmers in the study provided no cattle housing at all, and 76.7 percent relied on communal grazing of natural pastures with no sown or conserved feed.

A generalized linear model applied to calving interval painted a complementary picture of which cows breed back fastest. Age was significant, with cows aged four to eight years showing shorter intervals than animals older than eight, consistent with the declining fertility of aged cows and the delayed ovarian recovery of young ones. Parity also mattered: multiparous cows had shorter calving intervals than biparous cows, likely reflecting physiological adaptations from previous calvings that allow a faster return to estrus, whereas second-calf cows often need longer postpartum recovery. Most strikingly, breeding method proved influential. Cows bred by artificial insemination had significantly shorter calving intervals than those mated naturally, a difference the authors link to planned mating and timely insemination rather than to the biology of the semen itself. Yet in practice, natural mating dominated the district, and only a quarter of farmers kept any records, mostly health or visitor logs, leaving most producers blind to the reproductive trajectories of their own animals.

The findings carry clear implications for extension services and policy. Because housing, body condition, and management system all shaped pregnancy outcomes, interventions do not need to be high-tech to be transformative. Simple shelters, strategic supplementation to improve body condition before breeding, and a shift from tethering toward managed grazing or zero-grazing units could raise pregnancy rates substantially. Expanding access to artificial insemination, paired with sire selection that accounts for the size of indigenous dams, could simultaneously shorten calving intervals and reduce the dystocia rate that currently endangers both cows and calves. Basic record keeping, even a simple notebook of calving and mating dates, would allow farmers to identify non-productive animals and cull or treat them in time. The study’s authors recommend appropriate housing and breeding interventions as the priority actions for Namayingo and for comparable smallholder systems across the region.

Beyond the local context, the research contributes to a broader scientific conversation about why cattle fertility lags across African smallholder systems, where livestock underpin more than 70 percent of rural Ugandan livelihoods and cattle account for roughly 73 percent of the gross value of livestock output. Suboptimal reproduction ripples outward: fewer calves mean fewer replacement animals, less milk, less meat, lower household income, and diminished resilience against climate and market shocks. By identifying specific, modifiable risk factors in a non-traditional cattle-keeping district that transitioned from fishing to farming, the study demonstrates that reproductive decline in small herds is neither inevitable nor purely biological. It is, to a large degree, a management problem with management solutions, and the evidence from Namayingo suggests those solutions are well within reach of the farmers who need them most.

Subject of Research: Risk factors affecting reproductive efficiency of cattle in smallholder production systems in Namayingo district, Uganda

Article Title: Risk factors that undermine reproductive efficiency of cattle in smallholder production systems in Namayingo district in Uganda

Article References: Kigoonya, R., Baluka, S. A., Mugizi, D. R., & Kisira, E. (2026). Risk factors that undermine reproductive efficiency of cattle in smallholder production systems in Namayingo district in Uganda. Discover Animals, 3(1), Article 83. https://doi.org/10.1007/s44338-026-00241-8

Image Credits: AI Generated

DOI: 10.1007/s44338-026-00241-8

Keywords: cattle, reproductive efficiency, smallholder farmers, Uganda, calving interval, dystocia, body condition score, artificial insemination, animal housing, pregnancy status, indigenous breeds, livestock production