ABSTRACT The objective of this study was to evaluate the effect of milking hygiene practices, herd size, water hardness, and temperature-humidity index (THI) on the physicochemical and microbiological characteristics of raw milk, and standard plate count (SPC) in milking machines of dairy farms in the central region of Mexico. Data were collected from fifty-three dairy farms during one year. The evaluated effects included milking hygiene conditions (good, medium, poor), herd size (1-50, 51-100, 101-150, ≥151 heads), water hardness (soft or moderately hard), and THI (comfortable or stressful). The increase in milking hygiene produced greater milk yield (MY) and energy corrected milk (ECM) but lower protein content, and decreased the individual bacterial count (IBC) and somatic cell count (SCC). The MY, ECM, protein content, IBC, and SCC were higher on bigger farms. The use of soft water reduced MY, IBC, and SCC, but improved fat, lactose, total solids (TS), and non-fat solids (NFS). Heat stress negatively affected fat, protein, TS, NFS, acidity, freezing point (FP), SCC, and methylene blue dye reduction test. Poor milking hygiene contributes to higher SPC in milking machine parts. Water hardness and THI did not affect SPC in all milking machine parts. Proper milking hygiene practices, larger herd size, softer water, lower THI, and adequate cleaning and disinfection of the milking machine parts benefits the physicochemical and microbiological quality of the milk. practices temperaturehumidity temperature humidity (THI (SPC Mexico fiftythree fifty three year good, good (good medium poor, poor , poor) 150, 150 1 50, 50 (1-50 51100, 51100 51 100, 100 51-100 101150, 101150 101 101-150 151 ≥15 heads, heads heads) hard, hard hard) comfortable stressful. stressful . stressful) MY (MY ECM (ECM content IBC (IBC SCC. (SCC) fat lactose TS (TS) nonfat non NFS. NFS (NFS) acidity FP, FP (FP) test 15 5 (1-5 5110 10 51-10 10115 101-15 ≥1 (SCC (TS (NFS (FP (1- 511 51-1 1011 101-1 ≥ (1 51- 101- (

RESUMO: O estudo teve como objetivo avaliar o efeito do sexo e do peso ao abate sobre as características de carcaça e componentes não-carcaça de 1.489 cavalos (739 machos castrados e 750 fêmeas, classificados em oito grupos de acordo com o peso). Os dados foram analisados em um desenho inteiramente casualizado. Os semeadores apresentaram maior rendimento de carcaça quente (HCY) e fria (CCY) do que as fêmeas, porém o amarelecimento da gordura (b*) foi maior nas fêmeas. O peso ao abate (SW) afetou as características de carcaça. HCW, CCW, HCY e CCY aumentaram de acordo com o peso de abate, enquanto CL% foi menor em equinos com peso superior a 300 kg. Além disso, os componentes não-carcaça diminuíram com o aumento do peso dos cavalos. Em conclusão, sexo e peso corporal são fatores a serem considerados na produção de carne equina, uma vez que afetam as características da carcaça e seus componentes.

ABSTRACT: The study evaluated the effect of sex and slaughter weight on carcass traits and non-carcass components of 1,489 horses (739 geldings and 750 females, classified into eight groups according to their weight). Data were analyzed under a completely randomized design. Geldings had a higher (P < 0.05) hot carcass yield (HCY) and cold carcass yield (CCY) than females; however, fat yellowness values (b*) were greater (P < 0.05) in females. Slaughter weight (SW) affected the carcass characteristics. Hot carcass weight (HCW), cold carcass weight (CCW), HCY, and CCY increased (P < 0.05) in accordance with slaughter weight, while cool loss percentage (CL%) was lower (P < 0.05) in horses weighing more than 300 kg. In addition, the non-carcass components decreased (P < 0.05) as the weight of the horses increased. In conclusion, sex and body weight are factors to consider in the production of equine meat since they affect carcass characteristics and non-carcass components.

RESUMO: O objetivo deste estudo foi avaliar o efeito do gênero e peso vivo (PV) nas características da carcaça, componentes não-carcaça e cor da carne e gordura dos burros (Equus africanus asinus). Foram utilizados 189 animais de sexo castrado ou feminino. Os castrados tiveram peso de carcaça maior (P <0,05), molho de carcaça e uma gordura subcutânea luminosa (valor L) nas fêmeas. As fêmeas apresentaram perda de resfriamento maior (P <0,05), *valor de cor do músculo semitendinoso e b* valor de cor da gordura subcutânea. A gordura subcutânea apresentou maior (P <0,05) b* em animais idosos. Os burros com mais de 126kg de PV apresentaram maior peso de carcaça (P <0,05), curativo de carcaça e menor (P <0,05) perda de resfriamento em comparação com burros mais leves. O músculo semitendinoso e a gordura abdominal foram avermelhadas (P <0,05), maior valor de *, em burros mais pesados (>151kg). Enquanto isso, o PV não afetou a cor (valores de L *, a * e b *) de gordura subcutânea (P> 0,05). O peso maior da carcaça e o curativo com efeitos limitados em componentes não carcaça, cor de carne e gordura foram observados em castrados com peso vivo superior a 126kg.

ABSTRACT: One hundred eighty-nine Catalan crossbreed donkeys (Equus africanus asinus) were used to evaluate the effect of gender (gelding, n=106; or female, n=83) and live weight at slaughter (LW) (<100kg, n=25; 101 to 125kg, n=42; 126 to 150kg, n=85; and 151>kg, n=37) on carcass characteristics, non-carcass components and meat and fat color. Geldings had greater (P<0.05) carcass weight, carcass dressing and *L value of subcutaneous fat than females; but females had greater (P<0.05) cooling loss, a* value of semitendinosus muscle and b* value of subcutaneous fat. Donkeys with more than 126kg of LW showed greater (P<0.05) carcass weight and dressing and lower (P<0.05) cooling loss compared to lighter donkeys. The a* value of semitendinosus muscle and abdominal fat was greater in heaviest donkeys (>151kg). Meanwhile, the LW did not affect the color (L*, a* and b* values) of subcutaneous fat (P>0.05). These results suggested that both gender and live weight should be considered when producing meat from donkeys. It is advisable to use geldings weighing more than 126kg at slaughter to obtain the greatest weight and carcass yield.